大尺寸高精度三维控制网技术探讨

Discussion on Precise Three-Dimensional Coordinate Control Network in Field Large-Space Measurement

空间大尺寸机构的位置和姿态测量是诸多领域中不可或缺的必要环节。而传统的一维测量技术在精度、范围和速度上已经无法满足越来越高的需求,因此必须探索新的测量技术和方法。激光跟踪仪的单站坐标测量精度在局部范围内能够达到几十个微米量级,如果要在大尺度空间内同样实现该坐标测量精度,则需要建立全局的精密三维控制网。为了解算控制点全局坐标以及测站的位置和姿态参数,文中基于边角观测值和坐标转换模型建立了激光跟踪仪三维边角网整体平差模型。平差过程中,为了削弱激光跟踪仪测角误差的影响,建立了合理的角度和距离观测值权矩阵,为高精度距离观测值赋予较大的权值,从而对其进行约束。将该方法应用于宝钢不锈钢冷轧厂生产线的安装检测和轧辊轴线平行度测量,基于激光跟踪仪自由设站理论实现大尺寸精密三维控制网的建立,取得了良好效果。

The position and posture measurements of large facility are necessary works in many fields, but the old one-dimensional measuring technology is no longer to meet the growing requirement of measuring accuracy, range and speed, so new measuring technology and method should be studied. The point accuracy of micrometer can be realized by single station of laser tracker in small range, but it is necessary to establish precise three-dimensional control network to achieve the same high accuracy of coordinate measuring in large-space field. In order to get the points coordinate in centralized coordination, the position and posture parameters of each station, a three-dimensional control network adjustment model based on observed value and coordination transformation was established.In order to decrease the influence on control network adjustment from angel measuring error, the weight matrix of angel and distance based on high accuracy observed value of distance was established. This method was applied to facility installing and axis parallelism detecting in production line of BAOSTEEL. The construction of large-space precise three-dimensional control network was realized successfully based on the theory of free multi-station measuring by laser tracker.